Dont worry, just work harder...I think the pressure of IB 2 Quarter one for me was the reason I messed up my integration test. I got a 2 on it, just imagine! I felt terrible but at the end we had 2 summit Calculus papers and I scored a high 6 on differentiation and a 7 on Integration. That really saved my predicted score for math HL but it is a matter of perseverance and not feeling too damaged by one bad test score. I would advice you to do all Pearson textbook questions, and especially the past paper practice questions and also try to be attentive in every calculus class. But just being attentive, and doing h/w wasnt enough for me I figured out after the 2 I got on integration. I then used youtube videos.....JMK Patrick, and BlackpenRedpen.....they saved my calculus understanding like literally! Dont only depend on your teacher for help or our friends.....and I dont know why but everyone seemed so unhelpful in IB 2 Quarter 1...with all the college apps, IAs, SAT subjects preps.....and so I was like I will use videos and they really helped. My teacher's h/w is usually a ton of IB past paper questions to do to prepare for tests and she gives us. If you do all the past paper questions and understand 90% of the questions yourself, do most or ALL the questions on Pearson textbook, use your teachers, friends...BUT also realize that you can trust yourself to learn from online videos....then I am sure you will score a 6/7 on the tests. Calculus is hard though so cheer up.

I just finished all of calculus....I can tell you it differs among people but I found differentiation easy or lets say moderate. On the tests on differentiation, I had a 7, 4, 7 so it was quite good for me. However I got too relaxed and I was like Calculus is easyyy! then Integration came about and I got knocked hard! like extremely....never before in my life have I seen a level 2...but I got it. So I did find it hard catching up on all the integration, making me feel like this part of calculus was really hard. I did come back strong as I scored a 7 on a recent Integration test we did. However, calculus is by far the most demanding topic I have done so far in MathHL...let alone I am probably doing the CALCULUS option too! I dont think, there will be any other demanding topic like Calculus, but I must say Quarter 1 of IB 2 year had a lot with IAs, college applications, sat test preps...so that might have contributed to why I found integration so challenging. But the key is to depend on your self as much as your teacher....don't just walk into class and out and do h/w and except a good score in Math HL, esp calculus.

MATH HL is a must for a great preparation in engineering. If you can't cope with MATH HL, how exactly will you be able to cope with engineering maths, further calculus etc. So for engineering Math HL, Phy Hl and Chem HL are the best choices. I only take Math HL and Chem HL, if there was comp. science hl at my school, I would have done it as well but I decided that I keep Phy at SL because I want to head into a univeristy where introduction to physics is nearly a must but I know I will struggle with physics because I dropped it from HL.

I think you should stay in Physics HL. The first few test up till the end of mechanics were shocking but with effort, it does get better. Just practice a lot before the tests and throughout the topics.

If you are applying to the UK or high ranked US unis hence the ivy leagues, MIT etc.....Math Studies could really hurt your chances especially when you competing with very competent students from all over the world. For US unis, if you do great in the ACT/SAT tests then Math studies wouldnt hurt too much but once again most of the people scoring highly om these tests and applying to the top unis are probably doing AP classes or Math SL and even HL.
BTW in the US, I think a 5 in Math HL gives you credits and is better than a 6/7 in Math Sl not to mention Studies. This is because you are then likely to be prepared to do well and keep up with the structure of these Top unis whereby they really push their students to do well. Plus if you are getting 7s in Math SL or 5s in Math HL...the ACT/SAT Math test with some practice will be very easy to you.

Math and Physics HL are by far the most difficult 7s you can get especially getting consistent 7s in Math HL, you need to be spending well over 3 hours of your day doing math and even triple that in the weekends. Its very tough to maintain a consistent 6 and especially 7 in Math HL. The tests are just always so demanding and math HL is really a great test of how good your math skills are especially if you considered yourself good at Maths before the IB. Physics HL is hard in a different way; its either you get the concept or dont get it and in physics HL, if you didnt solidify your concepts in a topic, you will have a problem but I stll feel like Physics HL has not made me work as hard as Math HL has yet.

Yes its possible especially with Chem SL. It is quite an easy subject when you regularly review it, jot down good notes and spend your own time drawing together the concepts and connections within the topics. To be honest, all the hard stuff is in the HL section of the syllabus but Chem SL becomes easy given you enjoy the subject and give your efforts.

Econ is harder than Geography and in many cases a lot more tedious. About the level of difficulty that true, but whether you will enjoy it or not is subjective. Universities love to see students with economics, and other highly regarded subjects related to the university courses, it makes them look well-rounded. I think the best part of IB econ is the HL bit with calculations and graphs, the content can be a lot at times but it is generally an easier subject.

Do what you love, I really wanted to do that combination but feared the workload that would come so I dropped chem hl to econ hl. Now I have to pay to change courses and my parents wont do that. So I am stuck with econ HL, which I really dont enjoy and find it quite tedious. Choose what you like and commit yourself to it! Even though it's hard, you are eventually going to do better at something you are movitated to do and enjoy it.

The difficulty and weight comes with the content but also the difficulty and trickiness of the questions. It needs a lot of practice to catch those tricks in the Math HL questions. I dont do SL but from what I see from my friends, their questions are generally straight forward, not too much thinking but more of just applying some method to solve a question. Whereas HL questions are just so cruel and tend to have these tricks with every one of them. You cant just apply a formula without actually understanding it because HL questions tend to look deeper into your abstract problem solving skills with the tools you take. If you look at the HL Function topic questions compared to SL, you will see that SL questions are a joke compared to HL. However, smart and constant practice does work for both!